Method and device of network resource release processing

ABSTRACT

A method of network resource release processing is provided, which includes the following steps. After user equipment (UE) using idle mode signaling reduction (ISR) mechanism registers to two 3rd Generation Partnership Project (3GPP) communication networks, when the UE changes from the 3GPP network to a non-3GPP communication network, a serving gateway (serving GW) receives a message sent from a peer endpoint network element (NE), and deletes network resources established by the two 3GPP communication networks for the UE according to the message. A mobility management NE and a serving GW are also provided. Through the method and device of network resource release processing, the resources are released when the UE using the ISR mechanism changes from the 3GPP network to the non-3GPP communication network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/781,580, filed on May 17, 2010, which is a continuation ofInternational Patent Application No. PCT/CN2009/070143, filed on Jan.14, 2009, which claims priority to Chinese Patent Application No.200810025943.4, filed on Jan. 21, 2008 and Chinese Patent ApplicationNo. 200810215898.9, filed on Sep. 8, 2008, all of which are herebyincorporated by reference in their entireties.

FIELD OF THE TECHNOLOGY

The present invention relates to the field of electronic communication,and more particularly to a method of network resource releaseprocessing, a mobility management network element (NE), and a servinggateway (serving GW).

BACKGROUND OF THE INVENTION

Along with the development of communication technology, in order toenhance the competitiveness of future networks, the 3rd GenerationPartnership Project (3GPP) is researching a brand-new evolution network.Referring to FIG. 1, a system architecture of the evolution networkincludes the following.

An evolved universal mobile telecommunications system (UMTS) territorialradio access network (E-UTRAN) is configured to implement radio-relatedfunctions of the evolution network. A mobility management entity (MME)takes charge of mobility management of a control plane, which includesmanagement of user context and mobility state, and assignment of a usertemporary identity. A serving gateway (serving GW) is a user planeanchor point between 3GPP communication networks, and terminates theinterface towards E-UTRAN. A packet data network gateway (PDN GW) is auser plane anchor point between the 3GPP communication network and anon-3GPP communication network, and terminates the interface towards theexternal PDN. A policy and charging rule function (PCRF) is configuredto perform functions including policy control decision and flow basedcharging control. A home user server (HSS) is configured to storesubscription information of user.

A UMTS territorial radio access network (UTRAN) and a global system formobile communication/enhanced data rates for GSM evolution (GSM/EDGE)radio access network (GERAN) are configured to implement theradio-related functions in the existing general packet radio service(GPRS)/UMTS network. A serving GPRS supporting node (SGSN) is configuredto implement routing forward, mobility management, session management,user information storage, and other functions in the GPRS/UMTS network.

Non-3GPP Internet Protocol communication networks (non-3GPP IP Access)are communication networks defined by the non-3GPP organizations, forexample, a wireless local area network (WLAN), a worldwideinteroperability for microwave access (WiMAX), and a code divisionmultiple access (CDMA) network.

An authentication, authorization and accounting server (AAA server) isconfigured to execute access authentication, authorization, andaccounting functions on user equipment (UE).

In order to reduce mobility management processing of the UE among thedifferent communication networks, the processing of the inter systemmobility between the GERAN/UTRAN and the E-UTRAN (inter 3GPP accesssystem mobility) can be reduced through an idle mode signaling reduction(ISR) mechanism in a 3GPP communication network.

In conventional systems, when the user using the ISR mechanism moves toanother New MME, the New MME acquires context information of the UE froman Old SGSN and an Old MME. Then, the New MME judges whether the UE usesthe ISR mechanism, and notifies the HSS of using situation of the ISRmechanism. The HSS then notifies the Old MME to detach the user.

The processing processes of a 3GPP communication network are specific toa 3GPP communication network. When the UE moves to the non-3GPPcommunication network, the specific processing processes in the 3GPPcommunication network cannot be processed in the non-3GPP communicationnetwork, that is, resources of the UE in the 3GPP communication networkcannot be released.

SUMMARY OF THE INVENTION

The present invention is directed to a method of network resourcerelease processing, a mobility management NE, and a serving GW, so as torelease resources when a UE using an ISR mechanism changes from a 3GPPcommunication network to a non-3GPP communication network.

In an embodiment, the present invention provides a method of networkresource release processing, which includes the following steps.

After a UE using ISR mechanism registers to two 3GPP communicationnetworks, when the UE changes from the 3GPP network to a non-3GPPcommunication network, a serving GW receives a message sent from a peerendpoint NE, and deletes network resources established by the two 3GPPcommunication networks for the UE according to the message.

Correspondingly, in an embodiment, the present invention provides aserving GW, which includes a first message receiving unit and aprocessing unit.

The first message receiving unit is configured to receive a messageincluding indication information sent from a peer endpoint NE.

The processing unit is configured to delete network resourcesestablished by 3GPP communication networks for a UE according to themessage received by the first message receiving unit.

Correspondingly, in an embodiment, the present invention provides amobility management NE, which includes a second message receiving unit,a resource releasing unit, and a message sending unit.

The second message receiving unit is configured to receive a handovercomplete message sent from a non-3GPP communication network.

The resource releasing unit is configured to release resourcesestablished by 3GPP communication networks for a UE after the secondmessage receiving unit receives the handover complete message.

The message sending unit is configured to send a message includingindication information to a serving GW, and notify the serving GW torelease the network resources established for the UE.

Through the method and device of resource release processing when the UEusing the ISR mechanism changes to the non-3GPP communication networkaccording to the embodiments of the present invention, the problem thatthe user using the ISR mechanism cannot perform processes after movingfrom the 3GPP communication network to the non-3GPP communicationnetwork is solved, and the network resources occupied by the user arereleased when the UE using the ISR mechanism changes from the 3GPPcommunication network to the non-3GPP communication network, therebyimproving system processing capability and ensuring quality of service(QoS) for the user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system architectural view of an evolution network providedin a 3GPP;

FIG. 2 is a flow chart of a first embodiment of a method of networkresource release processing according to the present invention;

FIG. 3 is a flow chart of a second embodiment of the method of networkresource release processing according to the present invention;

FIG. 4 is a flow chart of a third embodiment of the method of networkresource release processing according to the present invention;

FIG. 5 is a flow chart of a fourth embodiment of the method of networkresource release processing according to the present invention;

FIG. 6 is a flow chart of a fifth embodiment of the method of networkresource release processing according to the present invention;

FIG. 7 is a flow chart of a sixth embodiment of the method of networkresource release processing according to the present invention;

FIG. 8 is a flow chart of a seventh embodiment of the method of networkresource release processing according to the present invention;

FIG. 9 is a schematic structural view of a serving GW according to anembodiment of the present invention; and

FIG. 10 is a schematic structural view of a mobility management NEaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention provides a method of network resource releaseprocessing, which includes the following steps. After a UE using ISRmechanism registers to two 3GPP communication networks, when the UEchanges (including being handed over) from the 3GPP communicationnetwork to a non-3GPP communication network (particularly, the UE movesto the non-3GPP network, the UE initiates a processing process ofattaching to the non-3GPP network in the non-3GPP network, or the UEinitiates the processing process of attaching to the non-3GPP network inthe 3GPP network), a serving GW receives a message sent from a peerendpoint NE, and deletes network resources established by the two 3GPPcommunication networks for the UE according to information included inthe message.

The message sent from the peer endpoint NE received by the serving GWincludes, but not limited to, the following two manners.

In a manner 1, when the peer endpoint NE is a PDN GW, the message sentfrom the peer endpoint NE is a delete bearer request message or abinding revocation indication message.

In a manner 2, when the peer endpoint NE is a mobility management NE ofthe 3GPP communication network, the message sent from the peer endpointNE is the delete bearer request message or a delete Packet Data Protocol(PDP) context request message.

The manner 2 particularly includes the following manners.

In manner 2.1, an HSS triggers the mobility management NE of the 3GPPcommunication network to send the delete bearer request message or thedelete PDP context request message to the serving GW.

In manner 2.2, the non-3GPP communication network triggers the mobilitymanagement NE of the 3GPP communication network to send the deletebearer request message or the delete PDP context request message to theserving GW.

In the following, technical solutions of the method of resource releaseprocessing when the UE using the ISR mechanism changes from the 3GPPcommunication network to the non-3GPP communication network, themobility management NE, and the serving GW are described in detail withaccompanying drawings.

In the manner 1, when the peer endpoint NE is the PDN GW, the messagesent from the peer endpoint NE is the delete bearer request message orthe binding revocation indication message.

FIG. 2 is a flow chart of a first embodiment of the method of networkresource release processing according to the present invention.Referring to FIG. 2, in this embodiment, for mobility management NEs oftwo 3GPP communication networks, a mobility management NE of a second3GPP communication network is an Old SGSN, and a mobility management NEof a first 3GPP communication network is an Old MME. When a UE using ISRmechanism in the 3GPP communication network moves from the 3GPP networkto a non-3GPP network, a PDN GW performs a resource release process. Themethod includes the following steps.

In Step S1, the UE performs a service process in the 3GPP network, andinitiates an attach session negotiation procedure when moving from the3GPP communication network to the non-3GPP communication network.

In Step S2, the PDN GW sends a message to a serving GW, in which wheninterface protocol between the serving GW and the PDN GW is GPRSTunneling Protocol (GTP), the message is a delete bearer requestmessage, and when the interface protocol between the serving GW and thePDN GW is Proxy Mobile Internet Protocol (PMIP), the message is abinding revocation indication message. The PDN GW may include a firstindication information in the delete bearer request message or thebinding revocation indication message, the first indication informationis configured to indicate that a communication network of the UE changesfrom the 3GPP communication network to the non-3GPP network, that is,the delete bearer request message or the binding revocation indicationmessage is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network. A particular manner of processingthe indication information is described as follows.

A Cause IE is set to a specific cause value (for example, Inter RATChange from 3GPP to non-3GPP), so as to indicate that the process iscaused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

Alternatively, a specific indication bit IE (for example, Inter RATChange from 3GPP to non-3GPP) is set, so as to indicate that the processis caused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

Alternatively, a Delete Type or a Revocation Type IE is set to aspecific value (for example, 1), so as to identify that the process iscaused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

In Step S3, after receiving the delete bearer request or the bindingrevocation indication message, according to the first indicationinformation in the message, the serving GW judges that the UE changesfrom the 3GPP communication network to the non-3GPP communicationnetwork, and the serving GW finds that the UE uses the ISR mechanism, sothe serving GW decides to deactivate the ISR mechanism of the UE (thatis, the serving GW decides that the UE does not use the ISR mechanism inthe 3GPP communication network and the non-3GPP communication network),performs a session negotiation on the resource release process with the3GPP communication network, and releases the resources of the UE in the3GPP.

It should be noted that when the PDN GW does not include the firstindication information in the delete bearer request or the bindingrevocation indication message, and after the serving GW finds that allbearers of the UE are requested to be released by the PDN GW, theserving GW considers that the bearer release is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork.

In Step S4, after completing the session negotiation with the 3GPPcommunication network, the serving GW releases the resources (includinguser plane resources and control plane resources) of the UE in the 3GPPcommunication networks on the serving GW, and returns a responsemessage, for example, a delete bearer response message or a bindrevocation acknowledgement message, to the PDN GW.

After receiving the response message, the PDN GW releases the 3GPPnetwork resources of the UE on the PDN GW, reserves the resources in thetarget non-3GPP communication network, and at the same time reservesresources assigned by the PDN GW for the UE, such as an IP address.

Referring to FIG. 2, the attach session negotiation procedure in Step S1particularly includes the following steps.

In Step S101, the UE registers to the Old MME of the first 3GPPcommunication network and the Old SGSN of the second 3GPP communicationnetwork, uses the ISR mechanism between the Old SGSN and the Old MME,and performs the service process through the serving GW and the PDN GW.

In Step S102, the UE moves to the non-3GPP communication network, andexecutes a specific attachment procedure, and authorization andauthentication programs of the non-3GPP communication network throughthe non-3GPP communication network.

In Step S103, a non-3GPP GW sends a Gateway control and QoS policy rulesrequest message to a PCRF to acquire a policy and charging control (PCC)rule used by the UE in the non-3GPP communication network. The PCRFreturns a Gateway control and QoS policy rules response message to thenon-3GPP GW, in which the message includes the PCC rule used by the UEin the non-3GPP communication network.

In this step, for a WLAN system, the non-3GPP GW is an evolved packetdata gateway (EPDG), for a WiMAX system, the non-3GPP GW is an accessservice network gateway (ASN GW), for a CDMA system, the non-3GPP GW isan access gateway (AGW), and for a high rate packet data (HRPD) network,the non-3GPP GW is a packet data serving node (PDSN).

Note: the PDSN is described to be an HRPD Serving gateway (HRPD servingGW) in some protocols.

In Step S104, the UE triggers a Layer 3 attachment procedure.

In Step S105, if interface between the non-3GPP GW and PDN GW uses thePMIP protocol, the non-3GPP GW sends a proxy binding update (BU) messageto the PDN GW. If interface between the UE and the PDN GW uses a ClientMobile Internet Protocol (CMIP), the UE sends a BU message to the PDNGW.

In Step S106, after receiving the message, the PDN GW acquires the PCCrule of the UE saved in the GW, and judges whether the PCC rule isrelevant to an access type of an IP-connectivity access network(IP-CAN). If yes, the PDN GW sends an IP-CAN session modificationrequest message to the PCRF to acquire the PCC rule used by the UE inthe non-3GPP communication network. The PCRF returns an IP-CAN sessionmodification acknowledgement message to the PDN GW, in which the messageincludes the PCC rule used by the UE in the non-3GPP communicationnetwork.

In Step S107, the PDN GW returns a proxy binding acknowledgement (BA)message to the non-3GPP GW, or the PDN GW returns the BA message to theUE.

In Step S108, the non-3GPP GW indicates the UE that the Layer 3attachment is completed.

Referring to FIG. 2, Step S3 particularly includes the following steps.

In Step S301, after the serving GW judges that the UE changes from the3GPP communication network to the non-3GPP communication networkaccording to the first indication information in the message sent fromthe PDN GW, the serving GW sends the delete bearer request message orthe delete PDP context request message to the Old MME of the first 3GPPcommunication network and the Old SGSN of the second 3GPP communicationnetwork. The serving GW may include the first indication information inthe delete bearer request message or the delete PDP context requestmessage, so as to indicate that the delete bearer request message or thedelete PDP context request message is caused by the UE changing from a3GPP communication network to a non-3GPP communication network. Theparticular manner of processing the first indication information isdescribed as follows.

A Cause IE is set to a specific cause value (for example, Inter RATChange from 3GPP to non-3GPP), so as to indicate that the process iscaused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

Alternatively, a specific indication bit IE (for example, Inter RATChange from 3GPP to non-3GPP) is set, so as to indicate that the processis caused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

Alternatively, a Delete Type IE is set to a specific value (for example,1), so as to identify that the process is caused by the UE changing froma 3GPP communication network to a non-3GPP communication network.

The serving GW may also include second indication information in thedelete bearer request message or the delete PDP context request message,so as to indicate that the delete bearer request message or the deletePDP context request message is caused by that the ISR mechanism of theUE is deactivated. A particular manner of processing the secondindication information is described as follows.

A Cause IE is set to a specific cause value (for example, ISR Deactive),so as to indicate that the delete bearer request message or the deletePDP context request message is caused by that the ISR mechanism of theUE is deactivated.

Alternatively, a specific indication bit IE or an identity IE (forexample, ISR Deactive) is set, so as to indicate that the delete bearerrequest message or the delete PDP context request message is caused bythat the ISR mechanism of the UE is deactivated.

Alternatively, a Delete Type IE is set to a specific value (for example,2), so as to identify that the delete bearer request message or thedelete PDP context request message is caused by that the ISR mechanismof the UE is deactivated.

In Step S302, after receiving the delete bearer request message or thedelete PDP context request message sent from the serving GW, the OldSGSN and the Old MME finds that the communication network of the UEchanges from the 3GPP communication network to the non-3GPPcommunication network or the ISR mechanism of the UE is deactivatedaccording to the first indication information or the second indicationinformation, the Old SGSN and the Old MME release the resources of theUE in the 3GPP networks. The process is described as follows.

The UE is detached, and a state of the UE is set to an“EMM-DEREGISTERED” state.

If the state of the UE is an activated state or a connected state in theOld SGSN or the Old MME, the Old SGSN and the Old MME notify the NEs ofthe 3GPP communication networks to release the resources (including aconnection resource and a bearer resource).

Alternatively, if the state of the UE is an idle state in the Old SGSNor the Old MME, the Old SGSN and the Old MME do not trigger a pagingprocess, and directly delete the resources locally.

The Old SGSN and the Old MME return the delete bearer response messageor the delete PDP context response message to the serving GW.

It should be noted that when the serving GW does not include the firstindication information or the second indication information in thedelete bearer request message or the delete PDP context request message,and after the Old MME and the Old SGSN find that all the bearers of theUE are requested to be released by the serving GW, the Old MME and theOld SGSN consider that the bearer release is caused by that the UEchanges from the 3GPP communication network to the non-3GPP network orthe ISR mechanism of the UE is deactivated.

In the above steps, if the Old SGSN or the Old MME finds that the UEregisters to a mobile switching center (MSC), in which the MSC mainlyprovides circuit switching calling function and mobility managementfunction for mobile users, when the MME or the SGSN detaches the UE, andthe detaching of the UE is caused by the UE changing from a 3GPPcommunication network to a non-3GPP communication network, the Old SGSNor the Old MME sends an international mobile user identity (IMSI) detachindication message to the MSC, so as to indicate the MSC to detach theUE.

FIG. 3 is a flow chart of a second embodiment of the method of networkresource release processing according to the present invention.Referring to FIG. 3, in this embodiment, a mobility management NE of asecond 3GPP communication network is an Old SGSN, and a mobilitymanagement NE of a first 3GPP communication network is an Old MME. Aftera UE using ISR mechanism moves from the 3GPP network to a non-3GPPnetwork, the UE initiates an attachment procedure through the non-3GPPnetwork. Then, a resource release process is performed. The methodincludes the following steps.

In Step s1, the UE performs a service process in the 3GPP communicationnetwork, and initiates an attach session negotiation procedure whenmoving from the 3GPP communication network to the non-3GPP communicationnetwork. The Step s1 includes the following steps.

In Step s101, the UE registers to the Old MME of the first 3GPPcommunication network and the Old SGSN of the second 3GPP communicationnetwork, uses the ISR mechanism between the Old SGSN and the Old MME,and performs the service process through the serving GW and the PDN GW.

In Step s102, the UE moves to the non-3GPP communication network, andexecutes a specific attachment procedure, and authorization andauthentication programs of the non-3GPP communication network throughthe non-3GPP communication network. The subsequent process is the sameas Steps S103-108 of the first embodiment, so it is not described here.

In Step s2, the PDN GW sends a message to a serving GW, in which wheninterface protocol between the serving GW and the PDN GW is a GTPprotocol, the message is a delete bearer request message, and when theinterface protocol between the serving GW and the PDN GW is a PMIPprotocol, the message is a binding revocation indication message. ThePDN GW may include first indication information in the message, thefirst indication information is configured to indicate that acommunication network of the UE changes from the 3GPP communicationnetwork to the non-3GPP network, that is, the delete bearer requestmessage or the binding revocation indication message is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork. A particular manner of processing the indication information isthe same as the description in Step S2 of the first embodiment, so it isnot described here.

In Step s3, after receiving the delete bearer request or the bindingrevocation indication message, the serving GW judges that the UE changesfrom the 3GPP communication network to the non-3GPP communicationnetwork according to the first indication information in the message(when the PDN GW does not include the first indication information inthe delete bearer request or the binding revocation indication message,and after the serving GW finds that all bearers of the UE are requestedto be released by the PDN GW, the serving GW considers that the bearerrelease is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network), the serving GW performs a sessionnegotiation on the resource release process with the 3GPP communicationnetwork, and releases the resources of the UE in the 3GPP. The stepparticularly includes the following steps.

In Step s301, the serving GW sends the delete bearer request message orthe delete PDP context request message to the Old MME of the first 3GPPcommunication network or the Old SGSN of the second 3GPP communicationnetwork. The serving GW may include the first indication information orsecond indication information in the delete bearer request message orthe delete PDP context request message. The particular manner ofprocessing the first indication information or the second indicationinformation is the same as the description in Step S301 of the firstembodiment, so it is not described here.

It should be noted that in the embodiment of the present invention, theprocess that the serving GW sends the delete bearer request message orthe delete PDP context request message to the Old SGSN of the second3GPP communication network is the same as the process that the servingGW sends the delete bearer request message or the delete PDP contextrequest message to the Old MME of the first 3GPP communication network.In this embodiment, only the process that the serving GW sends thedelete bearer request message to the Old MME of the first 3GPPcommunication network is set as an example for description. Thesituation that the serving GW sends the delete bearer request message tothe Old SGSN is not described here.

In Step s302, after receiving the delete bearer request message sentfrom the serving GW, according to the first indication information orthe second indication information, the Old MME of the first 3GPPcommunication network finds that the bearer delete is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork or the ISR mechanism of the UE is deactivated (when the servingGW does not include the first indication information or the secondindication information in the delete bearer request, and after the OldMME of the first 3GPP communication network finds that all bearers ofthe UE are requested to be released by the serving GW, the Old MME ofthe first 3GPP communication network considers that the bearer releaseis caused by the UE changing from a 3GPP communication network to anon-3GPP communication network or the ISR mechanism of the UE isdeactivated), and the Old MME of the first 3GPP communication networkfinds that the UE uses the ISR mechanism, the Old MME of the first 3GPPcommunication network deactivates the ISR mechanism of the UE, andnotifies the Old SGSN of the second 3GPP communication network to detachthe user and release the resources. The Old MME may send a detachrequest message to the Old SGSN of the second 3GPP communication networkto notify the Old SGSN to detach the user and release the resources. TheOld MME may include the first indication information or the secondindication information in the detach request message. A particularmanner of processing the first indication information is described asfollows.

A Cause IE is set to a specific cause value (for example, Inter RATChange from 3GPP to non-3GPP), so as to indicate that the detach requestmessage is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network.

Alternatively, a specific indication bit IE (for example, Inter RATChange from 3GPP to non-3GPP) is set, so as to indicate that the detachrequest message is caused by the UE changing from a 3GPP communicationnetwork to a non-3GPP communication network.

Alternatively, a Delete Type IE is set to a specific value (for example,1), so as to identify that the detach request message is caused by theUE changing from a 3GPP communication network to a non-3GPPcommunication network.

The second indication information is configured to indicate that therequest message is caused by that the ISR mechanism of the UE isdeactivated. The particular process is described in detail as follows.

The Cause IE is set to a specific cause value (for example, ISRDeactive), so as to indicate that the detach request message is causedby that the ISR mechanism of the UE is deactivated.

Alternatively, a specific indication bit IE or an identity IE (forexample, ISR Deactive) is set, so as to indicate that the detach requestmessage is caused by that the ISR mechanism of the UE is deactivated.

Alternatively, the Delete Type IE is set to a specific value (forexample, 2), so as to identify that the detach request message is causedby that the ISR mechanism of the UE is deactivated.

It should be noted that the Old MME may also send other messages tonotify the Old SGSN to detach the user and release the resources, forexample, the Old MME sends a delete resource request or a detachindication message to the Old SGSN to notify the Old SGSN to detach theuser and release the resources.

In Step s303, after the Old SGSN of the second 3GPP communicationnetwork receives the detach request message, the following process isperformed.

When the detach request message does not include the indicationinformation indicating that the detach request is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork or the ISR is deactivated, the Old SGSN sends the delete PDPcontext request (or the delete bearer request) message to the servingGW, and after receiving a PDP context response (or a delete bearerresponse) returned from the serving GW, the Old SGSN locally detachesthe user and deletes the bearer context resources, and sets a state ofthe UE to an “EMM-DEREGISTERED” state.

Alternatively, when the detach request message includes the indicationinformation indicating that the detach request is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork or the ISR is deactivated, and the serving GW releases all theresources without being notified by the Old SGSN of the resourcerelease, the Old SGSN does not send the delete PDP context request (orthe delete bearer request) message to the serving GW, but locallydetaches the user and deletes the bearer context resources, and sets thestate of the UE to the “EMM-DEREGISTERED” state.

Alternatively, when the detach request message includes the indicationinformation indicating that the detach request is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork or the ISR is deactivated, and the serving GW releases all theresources after being notified by the Old SGSN of the resource release,the Old SGSN sends the delete PDP context request (or the delete bearerrequest) message to the serving GW, and after receiving the PDP contextresponse (or the delete bearer response) returned from the serving GW,the Old SGSN locally detaches the user and deletes the bearer contextresources, and sets the state of the UE to the “EMM-DEREGISTERED” state.

In Step s304, the Old SGSN sends a detach response message to the OldMME.

In Step s305, after receiving the detach response message, the Old SGSNlocally detaches the user and deletes the bearer context resources (theOld SGSN may also release the bearer context resources after receivingthe delete bearer request message sent from the serving GW), sets thestate of the UE to the “EMM-DEREGISTERED” state, and returns a deletebearer response message to the serving GW.

In step s4, after completing the session negotiation with the 3GPPcommunication networks, the serving GW releases the resources (includinguser plane resources and control plane resources) of the UE in the 3GPPcommunication networks on the serving GW, and returns the delete bearerresponse message or a bind revocation acknowledgement message to the PDNGW.

After receiving the delete bearer response message or the bindrevocation acknowledgement message, the PDN GW releases the 3GPP networkresources of the UE on the PDN GW, reserves the resources in the targetnon-3GPP communication network, and at the same time reserves resourcesassigned by the PDN GW for the UE, such as an IP address.

In this embodiment, when the serving GW finds that the bearer delete iscaused by the UE changing from a 3GPP communication network to anon-3GPP communication network, and the serving GW finds that the UEuses the ISR mechanism, the serving GW has the following processmanners.

After receiving the delete bearer response message sent from the OldMME, the serving GW releases all the resources of the UE in the servingGW, in which the resources include the user plane resources and thecontrol plane resources (for example, the bearer context, and thecontrol plane resources of the serving GW towards the Old MME and theOld SGSN), and the Old SGSN needs not to notify the bearer resourcerelease.

Alternatively, the serving GW deactivates the ISR mechanism of the UE,deletes the resources (for example, the control plane resource of theserving GW towards the Old MME) in the serving GW relevant to the OldMME, but the serving GW does not delete the bearer context used by theUE, and does not delete the control plane resource of the serving GWtowards the Old SGSN. The serving GW releases all the resources (forexample, the bearer context and the control plane resource of theserving GW towards the Old SGSN) of the UE in the serving GW afterreceiving the delete bearer request message sent from the Old SGSN.

In the steps, if the Old SGSN or the Old MME finds that the UE registersto an MSC, when the MME or the SGSN detaches the UE, and the detachingof the UE is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network, the Old SGSN or the Old MME sendsan IMSI detach indication message to the MSC, so as to indicate the MSCto detach the UE.

In the manner 2.1, the HSS triggers the mobility management NE of the3GPP communication network to send the delete bearer request message orthe delete PDP context request message to the serving GW.

FIG. 4 is a flow chart of a third embodiment of the method of networkresource release processing according to the present invention.Referring to FIG. 4, in this embodiment, a mobility management NE of afirst 3GPP communication network is an Old SGSN, and a mobilitymanagement NE of a second 3GPP communication network is an Old MME. Themethod includes the following steps.

In Step F1, a UE performs a service process in the 3GPP communicationnetwork, and initiates an attach session negotiation procedure whenmoving from the 3GPP communication network to the non-3GPP communicationnetwork. The Step F1 includes the following steps.

In Step F101, the UE registers to the Old SGSN of the first 3GPPcommunication network and the Old MME of the second 3GPP communicationnetwork, uses the ISR mechanism between the Old SGSN and the Old MME,and performs the service process through a serving GW and a PDN GW.

In Step F102, the UE moves to the non-3GPP communication network, andexecutes a specific attachment procedure, and authorization andauthentication programs of the non-3GPP communication network. Thesubsequent process is the same as Steps S103-108 of the firstembodiment, so it is not described here.

In Step F103, the PDN GW or a non-3GPP GW registers a radio accessnetwork type (RAT type) of the non-3GPP communication network used bythe UE to an HSS through an AAA server.

In Step F2, the HSS finds that the RAT Type of the UE changes to the RATtype of the non-3GPP communication network, and the HSS finds that theUE uses the ISR mechanism, or the HSS finds that the Old SGSN of thefirst 3GPP communication network and the Old MME of the second 3GPPcommunication network register to the HSS, the HSS decides to detach theUE from the Old MME and the Old SGSN (that is, the HSS decides that theUE does not use the ISR mechanism in the 3GPP communication network andthe non-3GPP communication network), and sends a cancel location messageto the Old MME of the second 3GPP communication network and the Old SGSNof the first 3GPP communication network of the 3GPP communicationnetworks. The HSS may include first indication information in the cancellocation message, in which the first indication information isconfigured to indicate that a communication network of the UE changesfrom the 3GPP communication network to the non-3GPP communicationnetwork, that is, the cancel location message is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork. A particular manner of processing the first indicationinformation is described as follows.

A Cause IE is set to a specific cause value (for example, Inter RATChange from 3GPP to non-3GPP), so as to indicate that the CancelLocation is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network.

Alternatively, a specific indication bit IE (for example, Inter RATChange from 3GPP to non-3GPP) is set, so as to indicate that the CancelLocation is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network.

Alternatively, a Cancellation Type IE is set to a specific value (forexample, 1), so as to identify that the Cancel Location is caused by theUE changing from a 3GPP communication network to a non-3GPPcommunication network.

In Step F3, after receiving the cancel location message, the 3GPPcommunication network judges that the UE changes from the 3GPPcommunication network to the non-3GPP communication network according tothe first indication information in the message, performs a sessionnegotiation on the resource release process with the serving GW, andreleases the resources of the UE in the 3GPP.

In Step F4, after the serving GW completes the session negotiation onthe resource release process, if the releasing of the resources of the3GPP communication network side in the PDN GW need to be notified by theserving GW, the serving GW performs the session negotiation with the PDNGW, so as to indicate the PDN GW to release the resources.

In Step F3, the process through which the 3GPP communication networkperforms the session negotiation on the resource release process withthe serving GW and releases the resources of the UE in the 3GPPparticularly includes the following steps.

In Step F301, after receiving the cancel location message, the Old SGSNof the first 3GPP communication network and the Old MME of the second3GPP communication network detach the UE, and send a delete bearerrequest message or a delete PDP context request message to the servingGW. The Old SGSN and the Old MME include the first indicationinformation in the delete bearer request message or the delete PDPcontext request message, so as to indicate that the delete bearerrequest message or the delete PDP context request message is caused bythe UE changing from a 3GPP communication network to a non-3GPPcommunication network. A particular processing manner is described asfollows.

The Cause IE is set to a specific cause value (for example, Inter RATChange from 3GPP to non-3GPP), so as to indicate that the delete bearerrequest message or the delete PDP context request message is caused bythe UE changing from a 3GPP communication network to a non-3GPPcommunication network.

Alternatively, a specific indication bit IE (for example, Inter RATChange from 3GPP to non-3GPP) is set, so as to indicate that the deletebearer request message or the delete PDP context request message iscaused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

Alternatively, the Delete Type IE is set to a specific value (forexample, 1), so as to indicate that the delete bearer request message orthe delete PDP context request message is caused by the UE changing froma 3GPP communication network to a non-3GPP communication network.

In Step F302, the serving GW returns a delete bearer response or adelete PDP context response message to the Old MME and the Old SGSN.

After receiving the delete bearer request message or the delete PDPcontext request message sent from the Old SGSN and the Old MME, theserving GW finds that the communication network of the UE changes fromthe 3GPP communication network to the non-3GPP communication networkaccording to the first indication information, so as to release all theresources including user plane resources and control plane resources(including the control plane resources of the serving GW towards the OldSGSN and the Old MME) of the UE.

In Step F4, the process that the serving GW performs the sessionnegotiation with the PDN GW, and indicates the PDN GW to release theresources particularly includes the following steps.

In Step F401, the serving GW sends a message including the firstindication information to the PDN GW, in which when interface protocolbetween the serving GW and the PDN GW uses GTP protocol, the message isthe delete bearer request, when the interface protocol between theserving GW and the PDN GW uses PMIP protocol, the message is a proxy BU,and the serving GW sets a Lifetime in the proxy BU message to 0. Thefirst indication information indicates that the delete bearer request orthe proxy BU message is caused by the UE changing from a 3GPPcommunication network to a non-3GPP communication network. A particularprocessing manner for the first indication information is described asfollows.

The Cause IE is set to a specific cause value (for example, Inter RATChange from 3GPP to non-3GPP), so as to indicate that the process iscaused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

Alternatively, a specific indication bit IE (for example, Inter RATChange from 3GPP to non-3GPP) is set, so as to indicate that the processis caused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

Alternatively, the Delete Type or the Revocation Type IE is set to aspecific value (for example, 1), so as to identify that the process iscaused by the UE changing from a 3GPP communication network to anon-3GPP communication network.

In Step F402, after receiving the message, the PDN GW deletes theresources of the UE in the old 3GPP communication networks (for example,a binding cache entry resource or a bearer context of the old 3GPPcommunication network), reserves the resources in the target non-3GPPcommunication network, and at the same time reserves resources assignedby the PDN GW for the UE, such as an IP address. The PDN GW returns aresponse message (for example, a delete bearer response or a proxy BAmessage) to the serving GW.

In the steps, if the Old SGSN or the Old MME finds that the UE registersto an MSC, when the MME or the SGSN detaches the UE, and the detachingof the UE is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network, the Old SGSN or the Old MME sendsan IMSI detach indication message to the MSC, so as to indicate the MSCto detach the UE.

FIG. 5 is a flow chart of a fourth embodiment of the method of networkresource release processing according to the present invention.Referring to FIG. 5, in this embodiment, a mobility management NE of afirst 3GPP communication network is an Old SGSN, and a mobilitymanagement NE of a second 3GPP communication network is an Old MME. Themethod includes the following steps.

In Step f1, a UE performs a service process in the 3GPP communicationnetwork, and initiates an attach session negotiation procedure whenmoving from the 3GPP communication network to the non-3GPP communicationnetwork. The particular process is the same as the third embodiment asshown in FIG. 4, so it is not described here.

In Step f2, the HSS finds that an RAT Type of the UE changes to the RATtype of the non-3GPP communication network, the HSS decides to detachthe UE from the Old MME of the second 3GPP communication network or theOld SGSN of the first 3GPP communication network, and sends a cancellocation message to the Old MME of the second 3GPP communication networkor the Old SGSN of the first 3GPP communication network. The HSS mayinclude first indication information in the cancel location message. Aparticular manner of processing the first indication information isconsistent with the description in Step F2 of the third embodiment, soit is not described here.

It should be noted that the processing process of sending the cancellocation message including the first indication information to the OldMME of the second 3GPP communication network is the same as the processof sending the cancel location message including the first indicationinformation to the Old SGSN of the first 3GPP communication network. Inthis embodiment, the process of sending the cancel location messageincluding the first indication information to the Old SGSN of the first3GPP communication network is set as an example for description.

In Step f3, after receiving the cancel location message, the Old SGSN ofthe first 3GPP communication network judges that the UE changes from the3GPP communication network to the non-3GPP communication networkaccording to the first indication information in the message, performs asession negotiation on the resource release process with the serving GW,and releases the resources of the UE in the 3GPP. The Step f3particularly includes the following steps.

In Step f301, the Old SGSN of the first 3GPP communication network sendsa delete bearer request or a delete PDP context request message to theserving GW, and includes the first indication information in the messageto indicate that the delete bearer request or the delete PDP contextrequest message is caused by the UE changing from a 3GPP communicationnetwork to a non-3GPP communication network. The processing manner isthe same as that in the third embodiment.

After receiving the delete bearer request or the delete PDP contextrequest message, according to the first indication information, theserving GW finds that the bearer delete is caused by the UE changingfrom a 3GPP communication network to a non-3GPP communication network,and the serving GW finds that the UE uses the ISR mechanism, the servingGW then sends a delete bearer response or a delete PDP context responsemessage to the Old SGSN, and performs the following processes.

The serving GW releases all the resources including user plane resourcesand control plane resources (for example, the bearer context, thecontrol plane resources of the serving GW towards the Old MME of thesecond 3GPP communication network and towards the Old SGSN of the first3GPP communication network) of the UE in the serving GW, and the Old MMEof the second 3GPP communication network needs not to notify the bearerresource release.

Alternatively, the serving GW deactivates the ISR mechanism of the UE,and deletes the resources (for example, the control plane resource ofthe serving GW towards the Old SGSN) relevant to the Old SGSN of thefirst 3GPP communication network in the serving GW, but the serving GWdoes not delete the bearer context used by the UE, and does not deletethe control plane resource of the serving GW towards the Old MME of thesecond 3GPP communication network, and the serving GW releases all theresources (for example, the bearer context, the control plane resourceof the serving GW towards the Old MME) of the UE in the serving GW afterreceiving the delete bearer request message sent from the Old MME of thesecond 3GPP communication network.

In Step f302, after receiving the Cancel Location message sent from theHSS in Step f2, if the Old SGSN of the first 3GPP communication networkfinds that the UE uses the ISR mechanism, the Old SGSN of the first 3GPPcommunication network decides to deactivate the ISR mechanism of the UE,and notifies the Old MME of the second 3GPP communication network todetach the user, and the Old SGSN sends a detach request message to theOld MME of the second 3GPP communication network. The Old SGSN mayinclude the first indication information or second indicationinformation in the detach request message. The particular manner ofprocessing the first indication information is the same as thedescription in Step s302 of the second embodiment, so it is notdescribed here.

The second indication information indicates that the detach request iscaused by that the ISR mechanism of the UE is deactivated. Theparticular processing manner is the same as the description in Step s302of the second embodiment, so it is not described here.

It should be noted that the Old SGSN may also send other messages tonotify the Old MME to detach the user or release the resources, forexample, the Old SGSN sends a delete resource request or a detachindication message to the Old MME to notify the Old MME to detach theuser and release the resources.

In Step f303, after receiving the message, the Old MME of the second3GPP communication network locally detaches the user and deletes thebearer context resource, and sets a state of the UE to an“EMM-DEREGISTERED” state. If the Old MME finds that the UE uses the ISRmechanism, the Old MME performs the following processes.

When the detach request message does not include the first indicationinformation or the second indication information indicating that thedetach request is caused by the UE changing from a 3GPP communicationnetwork to a non-3GPP communication network or the ISR is deactivated,the Old MME sends the delete PDP context request (or the delete bearerrequest) message to the serving GW.

Alternatively, when the detach request message includes the firstindication information indicating that the detach request is caused bythe UE changing from a 3GPP communication network to a non-3GPPcommunication network or the ISR is deactivated, and the serving GWreleases all the resources without being notified by the Old MME of theresource release, the Old MME does not send the delete PDP contextrequest (or the delete bearer request) message to the serving GW.

Alternatively, when the detach request message includes the indicationinformation indicating that the detach request is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork or the ISR is deactivated, and the serving GW releases all theresources after being notified by the Old SGSN of the resource release,the Old MME sends the delete PDP context request (or the delete bearerrequest) message to the serving GW.

In Step f304, the Old MME of the second 3GPP communication networkreturns a detach response message to the Old SGSN of the first 3GPPcommunication network.

In Step f4, after the serving GW completes the session negotiation onthe resource release process, if the releasing of the resources of the3GPP communication network side in the PDN GW need to be notified by theserving GW, the serving GW performs the session negotiation with the PDNGW, and indicates the PDN GW to release the resources. The Step f4particularly includes the following steps.

Steps f401-f402 are the same as Steps F401-F402 of the third embodiment,so they are not described here.

In the steps, if the Old SGSN or the Old MME finds that the UE registersto an MSC, when the MME or the SGSN detaches the UE, and the detachingof the UE is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network, the Old SGSN or the Old MME sendsan IMSI detach indication message to the MSC, so as to indicate the MSCto detach the UE.

FIG. 6 is a flow chart of a fifth embodiment of the method of networkresource release processing according to the present invention.Referring to FIG. 6, in this embodiment, a mobility management NE of asecond 3GPP communication network is an Old SGSN, and a mobilitymanagement NE of a first 3GPP communication network is an Old MME. Themethod includes the following steps.

In Step g1, a UE performs a service process in the 3GPP network, andinitiates an attach session negotiation procedure when moving from the3GPP communication network to the non-3GPP communication network. Theparticular process is the same as the third embodiment as shown in FIG.4, so it is not described here.

In Step g2, an HSS finds that an RAT Type of the UE changes to the RATtype of the non-3GPP communication network, the HSS decides to detachthe UE from the Old MME or the Old SGSN, and sends a cancel locationmessage to the Old MME of the first 3GPP communication network or theOld SGSN of the second 3GPP communication network in the 3GPPcommunication networks. The HSS may include first indication informationin the cancel location message. A manner of processing the firstindication information is consistent with the description in Step F2 ofthe third embodiment, so it is not described here.

It should be noted that the processing process of sending the cancellocation message including the first indication information to the OldMME of the first 3GPP communication network is the same as the processof sending the cancel location message including the first indicationinformation to the Old SGSN of the second 3GPP communication network. Inthis embodiment, the process of sending the cancel location messageincluding the first indication information to the Old MME of the first3GPP communication network is set as an example for description.

In Step g3, after receiving the cancel location message, the Old MME ofthe first 3GPP communication network judges that the UE changes from the3GPP communication network to the non-3GPP communication networkaccording to the first indication information in the message, performs asession negotiation on the resource release process with the serving GW,and releases the resources of the UE in the 3GPP. The Step g3particularly includes the following steps.

In Step g301, after receiving the cancel location message, the Old MMEof the first 3GPP communication network sends a delete bearer PDPcontext request message or a delete PDP context request message to theserving GW, and includes the first indication information in the messageto indicate that the delete bearer request message or the delete PDPcontext request message is caused by the UE changing from a 3GPPcommunication network to a non-3GPP communication network. Theprocessing manner is the same as the description in Step F301 of thethird embodiment, so it is not described here.

In Step g302, after receiving the delete bearer request message or thedelete PDP context request message, according to the first indicationinformation, the serving GW finds that the bearer delete is caused bythe UE changing from a 3GPP communication network to a non-3GPPcommunication network, and the serving GW finds that the UE uses the ISRmechanism, the serving GW deactivates the ISR mechanism, and notifiesthe Old SGSN of the second 3GPP communication network to delete thebearer and detach the user. Particularly, the serving GW sends thedelete PDP context request message or the delete bearer request messageto the Old SGSN of the second 3GPP communication network, and theserving GW may include the first indication information or secondindication information in the message to indicate that the delete PDPcontext request message or the delete bearer request message is causedby the UE changing from a 3GPP communication network to a non-3GPPcommunication network or the ISR mechanism of the UE is deactivated. Theparticular process is the same as the description in Step S301 of thefirst embodiment, and it is not described here.

After receiving the delete bearer request or the delete PDP contextrequest message sent from the serving GW, tconhe Old SGSN of the second3GPP communication network finds that the bearer delete is caused by theUE changing from a 3GPP communication network to a non-3GPPcommunication network or the ISR mechanism of the UE is deactivatedaccording to the first indication information or the second indicationinformation, the Old SGSN may perform the following processes.

The UE is detached, and a state of the UE is set to an“EMM-DEREGISTERED” state.

If the state of the UE is an activated state or a connected state in theOld SGSN, the Old SGSN notifies the NE of the access network to releasethe resources (including a connection resource and a bearer resource),and returns a delete PDP context response message or a delete bearerresponse message to the serving GW.

Alternatively, if the state of the UE is an idle state in the Old SGSN,the Old SGSN does not trigger a paging process, but directly locallydeletes the resources, and returns the delete PDP context responsemessage or the delete bearer response message to the serving GW.

It should be noted that when the serving GW does not include the firstindication information or the second indication information in thedelete bearer request message or the delete PDP context request message,and after the Old SGSN finds that all the bearers of the UE arerequested to be released by the serving GW, the Old SGSN considers thatthe bearer release is caused by that the UE changes from the 3GPPcommunication network to the non-3GPP network.

In Step g303, the serving GW releases all the resources including userplane resources and control plane resources (including the control planeresources of the serving GW towards the Old SGSN of the second 3GPPcommunication network and towards the Old MME of the first 3GPPcommunication network) of the UE, and returns the delete bearer responsemessage or the delete PDP context response message to the Old MME.

In Step g4, after the serving GW completes the session negotiation onthe resource release process, if the releasing of the resources of the3GPP communication network side in the PDN GW need to be notified by theserving GW, the serving GW performs the session negotiation with the PDNGW, and indicates the PDN GW to release the resources. Step g4particularly includes the steps.

Steps g401-g402 are the same as Steps F401-F402 of the third embodiment,so they are not described here.

In the steps, if the Old SGSN or the Old MME finds that the UE registersto an MSC, when the MME or the SGSN detaches the UE, and the detachingof the UE is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network, the Old SGSN or the Old MME sendsan IMSI detach indication message to the MSC, so as to indicate the MSCto detach the UE.

In the manner 2.2, the non-3GPP communication network triggers themobility management NE of the 3GPP communication network to send thedelete bearer request message or the delete PDP context request messageto the serving GW.

FIG. 7 is a flow chart of a sixth embodiment of the method of networkresource release processing according to the present invention.Referring to FIG. 7, in this embodiment, a mobility management NE of afirst 3GPP communication network is an Old MME, and a mobilitymanagement NE of a second 3GPP communication network is an Old SGSN.After a UE using an ISR mechanism changes from the 3GPP network mobileto a non-3GPP network, the US initiates an attachment procedure throughthe 3GPP network. Then, a resource release process is performed. Themethod includes the following steps.

In Step H1, the UE performs a service process in the 3GPP communicationnetwork, and initiates an attach session negotiation procedure.

In Step H2, after the attach negotiate is completed, a non-3GPP GW or anon-3GPP access NE of the non-3GPP communication network sends ahandover complete message to the Old MME of the first 3GPP communicationnetwork or the Old SGSN of the second 3GPP communication network of the3GPP communication networks. The process that the non-3GPP GW or thenon-3GPP access NE sends the handover complete message to the Old MME ofthe first 3GPP communication network is the same as the process that thenon-3GPP GW or the non-3GPP access NE sends the handover completemessage to the Old SGSN of the second 3GPP communication network. Inthis embodiment, the process that the non-3GPP GW non-3GPP access NEsends the handover complete message to the Old MME of the first 3GPPcommunication network is set as an example for description.

In Step H3, after receiving the handover complete message, the 3GPPcommunication network performs a session negotiation on the resourcerelease process with a serving GW by sending a delete bearer requestmessage or a delete PDP context request message including firstindication information or third indication information, so as to releasethe resources. The first indication information is configured toindicate that a communication network of the UE changes from the 3GPPcommunication network to the non-3GPP communication network, and thethird indication information indicates that the resource release processis caused by an optimized handover.

In Step H4, after the serving GW completes the session negotiation onthe resource release process, if the releasing of the resources of the3GPP communication network side in a PDN GW need to be notified by theserving GW, the serving GW performs the session negotiation with the PDNGW, and indicates the PDN GW to release the resources.

Step H1 particularly includes the following steps.

In Step H101, the UE registers to the Old SGSN of the first 3GPPcommunication network and the Old MME of the first 3GPP communicationnetwork, uses the ISR mechanism between the Old SGSN and the Old MME,and performs the service process through the serving GW and the PDN GW.

In Step H102, the UE performs a specific attachment procedure, andauthorization and authentication programs of the non-3GPP communicationnetwork through the 3GPP communication network. If necessary, the UEexecutes an IP Security Protocol (IPSec) tunnel establishing procedure.

In Step H103, the non-3GPP GW sends a Gateway control and QoS policyrules request message to a PCRF to acquire a PCC rule used by the UE inthe non-3GPP communication network.

The PCRF returns a Gateway control and QoS policy rules response messageto the non-3GPP GW, in which the message includes the PCC rule used bythe UE in the non-3GPP communication network.

In the step, for a WLAN system, the non-3GPP GW is an EPDG, for a WiMAXsystem, the non-3GPP GW is an ASN GW, for a CDMA system, the non-3GPP GWis an AGW, and for an HRPD network, the non-3GPP GW is a PDSN.

In Step H104, the UE triggers a Layer 3 attachment procedure through the3GPP communication network.

In Step H105, the non-3GPP communication network completes the processof the Layer 3 attachment process, and returns a Layer 3 attach completemessage to the UE through the 3GPP communication network.

In Step H106, the UE moves to the non-3GPP communication network, andsends an access message relevant to the non-3GPP communication networkto the non-3GPP GW through the access NE in the non-3GPP communicationnetwork.

The process of Steps H107-H109 is the same as Steps S105-S107 in thefirst embodiment, so it is not described here.

Step H3 particularly includes the following steps.

In Step H301, after receiving the handover complete message sent fromthe non-3GPP network, the Old MME of the first 3GPP communicationnetwork sends the delete bearer request message or the delete PDPcontext request message including the first indication information tothe serving GW. The first indication information indicates that thedelete bearer request message or the delete PDP context request messageis caused by the UE changing from a 3GPP communication network to anon-3GPP communication network. The particular process is the same asthe description in Step F301 of the third embodiment, so it is notdescribed here.

It should be noted that the Old MME of the first 3GPP communicationnetwork may include the third indication information in the deletebearer request message or the delete PDP context request message, so asto indicate that the delete bearer request message or the delete PDPcontext request message is caused by the optimized handover. Theparticular processing manner is described as follows.

A Cause IE is set to a specific cause value (for example, “OptimizedHandover”), so as to indicate that the delete bearer request message orthe delete PDP context request message is caused by the optimizedhandover.

Alternatively, a specific indication bit IE or an identity bit IE (forexample, “Optimized Handover”) is set, so as to indicate that the deletebearer request message or the delete PDP context request message iscaused by the optimized handover.

Alternatively, a Delete Type IE is set to a specific value (for example,3), so as to indicate that the delete bearer request message or thedelete PDP context request message is caused by that the ISR mechanismof the UE is deactivated.

In Step H302, after receiving the delete bearer request message or thedelete PDP context request message, according to the first indicationinformation or the third indication information, the serving GW findsthat the bearer delete is caused by the UE changing from a 3GPPcommunication network to a non-3GPP communication network or theoptimized handover, and the serving GW finds that the UE uses the ISRmechanism, the serving GW deactivates the ISR mechanism, and notifiesthe Old SGSN of the second 3GPP communication network to delete thebearer and detach the user. The serving GW sends the delete PDP contextrequest message or the delete bearer request message including the firstindication information to the Old SGSN of the second 3GPP communicationnetwork. For the particular manner of processing the first indicationinformation, please refer to the description in Step S301 of the firstembodiment. If the serving GW does not include the indicationinformation in the delete bearer request message or the delete PDPcontext request message, and after the Old SGSN finds that all bearersof the UE are requested to be released by the serving GW, the Old SGSNconsiders that the bearer release is caused by the UE changing from a3GPP communication network to a non-3GPP communication network.

It should be noted that the serving GW may include second indicationinformation in the message, so as to indicate that the delete PDPcontext request message or the delete bearer request message is causedby that the ISR mechanism of the UE is deactivated. For the particularprocessing manner, please refer to the description in Step g302 of thefifth embodiment.

Alternatively, the serving GW may also include the third indicationinformation in the message, so as to indicate that the delete bearerrequest message or the delete PDP context request message is caused bythe optimized handover. The particularly manner is described as follows.

The Cause IE is set to a specific cause value (for example, “OptimizedHandover”), so as to indicate that the process is caused by theoptimized handover.

Alternatively, a specific indication bit IE or an identity bit IE (forexample, “Optimized Handover” or “Optimized Handover Flag”) is set, soas to indicate that the delete bearer request message or the delete PDPcontext request message is caused by the optimized handover.

Alternatively, the Delete Type IE is set to a specific value (forexample, 3), so as to indicate that the delete bearer request message orthe delete PDP context request message is caused by that the optimizedhandover.

In Step H303, after receiving the delete bearer request or the deletePDP context request message sent from the serving GW, according to thefirst indication information, the second indication information, or thethird indication information, the Old SGSN of the second 3GPPcommunication network finds that the bearer delete is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork, or is caused by the optimized handover, or is caused by thatthe ISR mechanism of the UE is deactivated. The process of the Old SGSNis the same as the process of the Old SGSN in Step g302 of the fifthembodiment, so it is not described here.

It should be noted that when the serving GW does not include the firstindication information, the second indication information, or the thirdindication information in the delete bearer request message or thedelete PDP context request message, and after the Old SGSN finds thatall the bearers of the UE are requested to be released by the servingGW, the Old SGSN considers that the bearer release is caused by that theUE changes from the 3GPP communication network to the non-3GPP network.

In Step H304, the serving GW releases all the resources including userplane resources and control plane resources (including the control planeresources of the serving GW towards the Old SGSN and the Old MME) of theUE, and returns a delete bearer response message or a delete PDP contextresponse message to the Old MME.

In Step H4, the process that the serving GW notifies the PDN GW torelease the resources particularly includes the following steps.

In Step H401, the serving GW sends a message including the firstindication information or the third indication information to the PDNGW, in which when interface protocol between the serving GW and the PDNGW uses GTP protocol, the message is the delete bearer request, when theinterface protocol between the serving GW and the PDN GW uses PMIPprotocol, the message is a proxy BU, and the serving GW sets a Lifetimein the proxy BU message to 0. The first indication information indicatesthat the delete bearer request or the proxy BU is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork. A particular process of the indication bit is the same as theprocess in Step F4 of the third embodiment, Step f4 of the fourthembodiment, and Step g4 of the fifth embodiment, so it is not describedhere.

The serving GW may also include the third indication information in themessage, so as to indicate that the delete bearer request message or theproxy BU message is caused by the optimized handover. The particularprocessing manner is described as follows.

The Cause IE is set to a specific cause value (for example, “OptimizedHandover”), so as to indicate that the process is caused by that theoptimized handover.

Alternatively, the specific indication bit or the identity bit IE (forexample, “Optimized Handover” or “Optimized Handover Flag”) is set, soas to indicate that the delete bearer request message or the proxy BUmessage is caused by the optimized handover.

Alternatively, the Delete Type or the an Update Type IE is set to aspecific value (for example, 3), so as to represent that the deletebearer request message or the proxy BU message is caused by theoptimized handover.

In Step H402, after receiving the message, the PDN GW deletes theresources of the UE in the old 3GPP communication network (for example,a binding cache entry resource or a bearer context of the old 3GPPcommunication network), reserves the resources in the target non-3GPPcommunication network, and at the same time reserves resources assignedby the PDN GW for the UE, such as an IP address. The PDN GW returns aresponse message (for example, a delete bearer response or a proxy BAmessage) to the serving GW.

In the steps, if the Old SGSN or the Old MME finds that the UE registersto an MSC, when the MME or the SGSN detaches the UE, and the detachingof the UE is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network, the Old SGSN or the Old MME sendsan IMSI detach indication message to the MSC, so as to indicate the MSCto detach the UE.

FIG. 8 is a flow chart of a seventh embodiment of the method of networkresource release processing according to the present invention.Referring to FIG. 8, in this embodiment, a mobility management NE of afirst 3GPP communication network is an Old MME, and a mobilitymanagement NE of a second 3GPP communication network is an Old SGSN.After a UE using an ISR mechanism changes from the 3GPP network mobileto a non-3GPP network, the US initiates an attachment procedure throughthe 3GPP network. Then, a resource release process is performed. Themethod includes the following steps.

In Step h1, the UE performs a service process in the 3GPP communicationnetwork, and initiates an attach session negotiation procedure throughthe 3GPP communication network. The particular processing procedure isthe same as Step H1 in the sixth embodiment, so it is not describedhere.

In Step h2, after the attach negotiate is completed, a non-3GPP GW or anon-3GPP access NE of the non-3GPP communication network sends ahandover complete message to the Old MME of the first 3GPP communicationnetwork or the Old SGSN of the second 3GPP communication network of the3GPP communication networks. The process that the non-3GPP GW or thenon-3GPP access NE sends the handover complete message to the Old MME ofthe first 3GPP communication network is the same as the process that thenon-3GPP GW or the non-3GPP access NE sends the handover completemessage to the Old SGSN of the second 3GPP communication network. Inthis embodiment, the process that the non-3GPP GW non-3GPP access NEsends the handover complete message to the Old MME of the first 3GPPcommunication network is set as an example for description.

In Step h3, after receiving the handover complete message, the Old MMEof the first 3GPP communication network performs a session negotiationon the resource release process with a serving GW by sending a deletebearer request message or a delete PDP context request message includingfirst indication information or third indication information, so as torelease the resources. The first indication information is configured toindicate that a communication network of the UE changes from the 3GPPcommunication network to the non-3GPP communication network, and thethird indication information indicates that the resource release processis caused by an optimized handover.

In Step h4, after the serving GW completes the session negotiation onthe resource release process, if the releasing of the resources of the3GPP communication network side in a PDN GW need to be notified by theserving GW, the serving GW performs the session negotiation with the PDNGW, so as to indicate the PDN GW to release the resources. The processis the same as the process in Step H4 of the sixth embodiment, so it isnot described here.

Step h3 particularly includes the following steps.

In Step h301, after receiving the handover complete message, the Old MMEof the first 3GPP communication network sends the delete bearer requestmessage or the delete PDP context request message to the serving GW.

The Old MME includes the first indication information in the message, soas to indicate that the delete bearer request message or the delete PDPcontext request message is caused by the UE changing from a 3GPPcommunication network to a non-3GPP communication network. Theparticular process is the same as the description in Step F301 of thethird embodiment, so it is not described here.

It should be noted that the Old MME may include the third indicationinformation in the message, so as to indicate that the delete bearerrequest message or the delete PDP context request message is caused bythe optimized handover. For the particular process, please refer to thedescription in Step H301 of the sixth embodiment, so it is not describedhere.

After receiving the delete bearer request message or the delete PDPcontext request message, according to the first indication informationor the third indication information, the serving GW finds that thebearer delete is caused by the UE changing from a 3GPP communicationnetwork to a non-3GPP communication network or the optimized handover,and the serving GW finds that the UE uses the ISR mechanism, the servingGW then processes in the following manners.

The serving GW releases all the resources including user plane resourcesand control plane resources (including the bearer context, and thecontrol plane resources of the serving GW towards the Old MME of thefirst 3GPP communication network and the Old SGSN of the second 3GPPcommunication network) of the UE in the serving GW, and the Old SGSNneeds not to notify the bearer resource release.

Alternatively, the serving GW deactivates the ISR mechanism of the UE,and deletes the resources (for example, the control plane resource ofthe serving GW towards the Old MME) in the serving GW relevant to theOld MME, but the serving GW does not delete the bearer context used bythe UE, and does not delete the control plane resource of the serving GWtowards the Old SGSN. The serving GW releases all the resources (forexample, the bearer context and the control plane resource of theserving GW towards the Old SGSN) of the UE in the serving GW afterreceiving the delete bearer request message or the delete PDP contextrequest message sent from the Old SGSN.

Alternatively, in Step h302, after receiving the handover completemessage sent from the NE in the non-3GPP communication network in Steph2, when the Old MME of the first 3GPP communication network finds thatthe UE uses the ISR mechanism, the Old MME decides to deactivate the ISRmechanism of the UE, notifies the Old SGSN of the second 3GPPcommunication network to detach the user, and sends a detach requestmessage to the Old SGSN of the second 3GPP communication network.

The Old MME may include the first indication information in the detachrequest message, so as to indicate that the detach request message iscaused by the UE changing from a 3GPP communication network to anon-3GPP communication network. For the particular process, please referto the description in Step s302 of the second embodiment, so it is notdescribed here.

It should be noted that the Old MME may include second indicationinformation in the detach request message, so as to indicate that thedetach request message is caused by that the ISR mechanism of the UE isdeactivated. For the particular process, please refer to the descriptionof Step s302 in the second embodiment, so it is not described here. TheOld MME may also include the third indication information in themessage, so as to indicate that the detach request message is caused bythe optimized handover. The particular process may be described asfollows.

A Cause IE is set to a specific cause value (for example, “OptimizedHandover”), so as to indicate that the detach request message is causedby the optimized handover.

Alternatively, a specific indication bit IE or an identity bit IE (forexample, “Optimized Handover” or “Optimized Handover Flag”) is set, soas to indicate that the detach request message is caused by theoptimized handover.

Alternatively, a Delete Type IE is set to a specific value (for example,3), so as to indicate that the detach request message is caused by theoptimized handover.

It should be noted that the Old MME may send other messages to notifythe Old SGSN to detach the user and release the resources, for example,the Old MME sends a delete resource request or a detach indicationmessage to the Old SGSN to notify the Old SGSN to detach the user andrelease the resources.

In Step h303, after receiving the detach message, the Old MME locallydetaches the user and deletes a bearer context resource, and sets astate of the UE to an “EMM-DEREGISTERED” state. If the Old MME findsthat the UE uses the ISR mechanism, the Old MME may perform thefollowing processes.

When the detach request message does not include the first indicationinformation, the second indication information, or the third indicationinformation indicating that the detach request is caused by the UEchanging from a 3GPP communication network to a non-3GPP communicationnetwork, or is caused by that the ISR is deactivated, or is caused bythe optimized handover, the Old MME sends the delete PDP context request(or the delete bearer request) message to the serving GW.

Alternatively, when the detach request message includes the firstindication information, the second indication information, or the thirdindication information indicating that the detach request is caused bythe UE changing from a 3GPP communication network to a non-3GPPcommunication network, or is caused by the optimized handover, or iscaused by that the ISR is deactivated, and the serving GW releases allthe resources without being notified by the Old MME of the resourcerelease, the Old MME does not send the delete PDP context request (orthe delete bearer request) message to the serving GW.

Alternatively, when the detach request message includes the firstindication information, the second indication information, or the thirdindication information indicating that the detach request is caused bythe UE changing from a 3GPP communication network to a non-3GPPcommunication network, is caused by the optimized handover, or is causedby that the ISR is deactivated, and the serving GW releases all theresources after being notified by the Old MME of the resource release,the Old MME sends the delete PDP context request (or the delete bearerrequest) message to the serving GW.

In Step h304, the Old MME returns a detach response message to the OldSGSN.

In the steps, if the Old SGSN or the Old MME finds that the UE registersto an MSC, when the MME or the SGSN detaches the UE, and the detachingof the UE is caused by the UE changing from a 3GPP communication networkto a non-3GPP communication network, the Old SGSN or the Old MME sendsan IMSI detach indication message to the MSC, so as to indicate the MSCto detach the UE.

Based on the session negotiation on the resource release process betweenthe serving GW and the 3GPP communication network triggered by thenon-3GPP network, the resources are released when the user using the ISRmechanism in the 3GPP communication network is handed over to thenon-3GPP communication network, the existing relevant NEs need to bemodified, and functions need to be expanded.

Referring to FIG. 9, a serving GW according to the present invention isshown, which includes a first message receiving unit 1 and a processingunit 2.

The first message receiving unit 1 is configured to receive a messageincluding indication information sent from a peer endpoint NE (includinga PDN GW, an Old MME, or an Old SGSN).

The processing unit 2 is configured to delete network resourcesestablished by 3GPP communication networks for a UE according to themessage received by the first message receiving unit 1.

The processing unit 2 includes an indication bit analyzing unit 21, aresource deleting unit 22, and a session negotiation unit 23.

The indication bit analyzing unit 21 is configured to judge whether todelete the network resources established by the 3GPP access networks forthe UE according to the indication information in the message receivedby the first message receiving unit 1.

The resource deleting unit 22 is configured to delete the networkresources established by the 3GPP communication networks for the UE onthe serving GW, when an analysis result of the indication bit analyzingunit 21 is yes.

The session negotiation unit 23 is configured to notify mobilitymanagement NEs of the 3GPP communication networks to release the networkresources established for the UE when the analysis result of theindication bit analyzing unit 21 is yes.

The session negotiation unit 23 includes a sending unit 231 and areceiving unit 232.

The sending unit 231 is configured to send a delete bearer requestmessage or a delete PDP context request message to the mobilitymanagement NEs of the 3GPP communication networks, so as to notify themobility management NEs to release the resources.

The receiving unit 232 is configured to receive a delete bearer responsemessage or a delete PDP context response message returned from themobility management NEs.

In this embodiment, the indication information includes first indicationinformation, second indication information, or third indicationinformation.

The first indication information is configured to indicate that acommunication network of the UE changes from the 3GPP communicationnetwork change to a non-3GPP communication network.

The second indication information is configured to indicate that an ISRof the UE is deactivated.

The third indication information is configured to indicate an optimizedhandover.

The message sent from the peer endpoint NE includes a delete bearerrequest message or a binding revocation indication message sent from aPDN GW; or the delete bearer request message or the delete PDP contextrequest message sent from the mobility management NEs of the 3GPPcommunication networks.

Referring to FIG. 10, a mobility management NE according to the presentinvention is shown, which includes a second message receiving unit 31, aresource releasing unit 32, and a message sending unit 33.

The second message receiving unit 31 is configured to receive a cancellocation message sent from an HSS or a handover complete message sentfrom a non-3GPP communication network, in which the cancel locationmessage may include first indication information, so as to indicate thata communication network of a UE changes from a 3GPP communicationnetwork to the non-3GPP communication network.

The resource releasing unit 32 is configured to release resourcesestablished by the 3GPP communication networks for the UE after thesecond message receiving unit 31 receives the cancel location message orthe handover complete message.

The message sending unit 33 is configured to send a message includingindication information to a serving GW, and notify the serving GW torelease the resources.

In another embodiment of the present invention, the mobility managementNE further includes a resource release notification unit 34.

The resource release notification unit 34 is configured to notify amobility management NE of the other 3GPP communication network torelease the network resources established for the UE. A detach requestmessage may include first indication information, second indicationinformation, or third indication information. The first indicationinformation is configured to indicate that the communication network ofthe UE changes from the 3GPP communication network to the non-3GPPcommunication network, the second indication information is configuredto indicate that an ISR of the UE is deactivated, and the thirdindication information is configured to indicate an optimized handover.

In this embodiment, the indication information includes the firstindication information, the second indication information, or the thirdindication information.

The first indication information is configured to indicate that thecommunication network of the UE changes from the 3GPP communicationnetwork change to the non-3GPP communication network.

The second indication information is configured to indicate that the ISRof the UE is deactivated.

The third indication information is configured to indicate the optimizedhandover.

In this embodiment, the message including the indication information isa delete bearer request message or a delete PDP context request message.

It should be noted that the mobility management NE according to theembodiments of the present invention is the MME or the SGSN.

Through the method of resource release processing and the relevantdevices according to the embodiments of the present invention, therequest message includes the indication information indicating that theUE using the ISR mechanism changes or is handed over from the 3GPPcommunication network to the non-3GPP communication network, so as toindicate the corresponding NEs to perform the processes, such that theproblem of the prior art that the user using the ISR mechanism cannotperform processes after moving from the 3GPP communication network tothe non-3GPP communication network is solved, and the old networkresources are released when the UE using the ISR mechanism changes fromthe 3GPP communication network to the non-3GPP communication network,thereby improving a system processing capability and ensuring a qualityof service (QoS) of the user.

The above descriptions are merely preferred embodiments of the presentinvention. It should be noted by persons of ordinary skill in the artthat modifications and improvements may be made without departing fromthe principle of the present invention, which should be construed asfalling within the scope of the present invention.

1. A method of network resource release processing, comprising:receiving, by a serving gateway (serving GW), a message sent from a peerendpoint network element (NE), when a user equipment (UE) changes from a3rd Generation Partnership Project (3GPP) network to a non-3GPP network,wherein the UE using IDLE MODE SIGNALING REDUCTION (ISR) mechanismregisters to two 3GPP communication networks; and deleting networkresources established by the two 3GPP communication networks for the UEaccording to the message.
 2. The method according to claim 1, whereinthe receiving, by the serving GW, the message sent from the peerendpoint NE comprises: receiving, by the serving GW, a delete bearerrequest message or a binding revocation indication message sent from apacket data network gateway (PDN GW), wherein the delete bearer requestmessage or the binding revocation indication message includes a firstindication information indicating that a communication network of the UEchanges from the 3GPP communication network to the non-3GPPcommunication network.
 3. The method according to claim 2, wherein thedeleting the network resources established by the two 3GPP communicationnetworks for the UE comprises: sending, by the serving GW, the deletebearer request message or a delete Packet Data Protocol (PDP) contextrequest message to notify mobility management NEs of the two 3GPPcommunication networks to release the network resources established forthe UE; receiving, by the mobility management NEs of the two 3GPPcommunication networks, the delete bearer request message or the deletePDP context request message; and releasing the resources of the UE inthe two 3GPP communication networks.
 4. The method according to claim 3,wherein the releasing the resources used by the UE comprises: detaching,by the mobility management NEs of the two 3GPP communication networks,the UE.
 5. The method according to claim 3, wherein the releasing theresources used by the UE comprises: notifying, by at least one of themobility management NEs of the two 3GPP communication networks, a mobileswitching center (MSC) to detach the UE.
 6. The method according toclaim 2, wherein the deleting the network resources established by thetwo 3GPP communication networks for the UE comprises: sending, by theserving GW, the delete bearer request message or a delete PDP contextrequest message to notify a mobility management NE of one of the two3GPP communication networks to release the network resources establishedfor the UE; and receiving, by the mobility management NE, the deletebearer request message or the delete PDP context request message,deleting the resources used by the UE, and sending a message to notify amobility management NE of the other 3GPP communication network torelease the resources.
 7. The method according to claim 6, wherein thereleasing the resources used by the UE comprises: detaching, by themobility management NEs of two the 3GPP communication networks, the UE.8. The method according to claim 1, wherein the deleting the networkresources established by the two 3GPP communication networks for the UEcomprises: sending, by the serving GW, a delete bearer request messageor a delete Packet Data Protocol (PDP) context request message to notifymobility management NEs of the two 3GPP communication networks torelease the network resources established for the UE; receiving, by themobility management NEs of the two 3GPP communication networks, thedelete bearer request message or the delete PDP context request message;and releasing the resources of the UE in the two 3GPP communicationnetworks.
 9. The method according to claim 8, wherein the releasing theresources used by the UE comprises: detaching, by the mobilitymanagement NEs of the two 3GPP communication networks, the UE.
 10. Themethod according to claim 8, wherein the releasing the resources used bythe UE comprises: notifying, by at least one of the mobility managementNEs of the 3GPP communication networks, a mobile switching center (MSC)to detach the UE.
 11. The method according to claim 1, furthercomprising: sending, by the non-3GPP communication network, a handovercomplete message to a mobility management NE of any one of the two 3GPPcommunication networks.
 12. The method according to claim 11, furthercomprising: sending, by the mobility management NE of one 3GPPcommunication network receiving the handover complete message, a messageto a mobility management NE of the other 3GPP communication network tonotify the mobility management NE to release the network resourcesestablished for the UE.
 13. The method according to claim 11, furthercomprising: receiving, by the serving GW, a delete bearer requestmessage or a delete PDP context request message sent from a mobilitymanagement NE of one of the two 3GPP communication networks, and sendingthe delete bearer request message or the delete PDP context requestmessage to a mobility management NE of the other 3GPP communicationnetwork to notify the mobility management NE to release the networkresources established for the UE.
 14. A serving gateway (serving GW),comprising: a first message receiving unit, configured to receive amessage including indication information sent from a peer endpointnetwork element (NE); and a processing unit, configured to deletenetwork resources established by two 3rd Generation Partnership Project(3GPP) communication networks for user equipment (UE) according to themessage received by the first message receiving unit.
 15. The serving GWaccording to claim 14, wherein the processing unit comprises: anindication bit analyzing unit, configured to determine whether to deletethe network resources established by the two 3GPP communication networksfor the UE according to the indication information in the messagereceived by the first message receiving unit; a resource deleting unit,configured to delete the network resources established by the two 3GPPcommunication networks for the UE on the serving GW, when an analysisresult of the indication bit analyzing unit is yes; and a sessionnegotiation unit, configured to notify mobility management NEs of thetwo 3GPP communication network to release the network resourcesestablished for the UE when the analysis result of the indication bitanalyzing unit is yes.
 16. The serving GW according to claim 15, whereinthe session negotiation unit comprises: a sending unit, configured tosend a delete bearer request message or a delete Packet Data Protocol(PDP) context request message to the mobility management NEs of the 3GPPcommunication networks, so as to notify the mobility management NEs torelease the network resources established for the UE; and a receivingunit, configured to receive a delete bearer response message or a deletePDP context response message returned from the mobility management NEs.17. The serving GW according to claim 16, wherein the message includingindication information sent from the peer endpoint NE comprises: adelete bearer request message or a binding revocation indication messagesent from a packet data network gateway (PDN GW); or the delete bearerrequest message or the delete PDP context request message sent from themobility management NEs of the 3GPP communication networks.